Key events in the history of your database include starting the database, changing the structure of the database, executing certain utilities, and encountering errors. When a key event occurs, details of the event are written to your database log file. When you enable your database to save key events, the information written to the log file is also copied into the _KeyEvt table in the database. The details of key events provide insight into critical moments in the history of your database.
Having the details of key events preserved is useful in the diagnosis of issues, either independently, or with the assistance of Progress technical support. Saving key events in the _KeyEvt table ensures that vital information is not lost when your log file is truncated or deleted. It also provides quick access to information that is otherwise embedded within your log file, possibly in the middle of millions of log file entries.